We introduced ectopic gene expression/knockdown through the RCAS virus, because of its lineage specific delivery in a receptor dependent way. To do this, the gene expression cassettes were cloned into the RCAS genome as previously described. We adopted and validated the RCAS virus strains RCAS-IDH1WT-shTrp53 and RCAS-IDH1R132H-shTrp53 to allow the expression of IDH1 mutant and Trp53 genetic silencing. The RCAS-U6-gRNA-PDGFb construct was a kind gift from Dr. Squatrito, and it allows gRNA and PDGFb spontaneous expression in vivo. We will also optimize RCAS plasmids strategy for gene editing and IDH1-mutated glioma modeling. New vector strategies, such as RCAS-gRNA, RCAS-IDH1-2A-PDGFb will be developed for further tumor modeling. At this stage, we have confirmed the tumor induction by using the RCAS-PDGFb and RCAS-IDH1-shTrp53 constructs in Ntva+/+, Ink4a-Arf-/- mice with predictable disease outcome. Moreover, we have also established a gRNA targeting strategy based on RCAS-U6-gRNA-PDGFb construct and validate the targeting efficacy in mouse genome.